1 files changed, 239 insertions, 0 deletions

diff --git a/fs/sysv/balloc.c b/fs/sysv/balloc.c
new file mode 100644
index 000000000000..9a6ad96acf27
--- /dev/null
+++ b/fs/sysv/balloc.c
@@ -0,0 +1,239 @@
+/*
+ *  linux/fs/sysv/balloc.c
+ *
+ *  minix/bitmap.c
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext/freelists.c
+ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
+ *
+ *  xenix/alloc.c
+ *  Copyright (C) 1992  Doug Evans
+ *
+ *  coh/alloc.c
+ *  Copyright (C) 1993  Pascal Haible, Bruno Haible
+ *
+ *  sysv/balloc.c
+ *  Copyright (C) 1993  Bruno Haible
+ *
+ *  This file contains code for allocating/freeing blocks.
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/string.h>
+#include "sysv.h"
+
+/* We don't trust the value of
+   sb->sv_sbd2->s_tfree = *sb->sv_free_blocks
+   but we nevertheless keep it up to date. */
+
+static inline sysv_zone_t *get_chunk(struct super_block *sb, struct buffer_head *bh)
+{
+        char *bh_data = bh->b_data;
+
+        if (SYSV_SB(sb)->s_type == FSTYPE_SYSV4)
+                return (sysv_zone_t*)(bh_data+4);
+        else
+                return (sysv_zone_t*)(bh_data+2);
+}
+
+/* NOTE NOTE NOTE: nr is a block number _as_ _stored_ _on_ _disk_ */
+
+void sysv_free_block(struct super_block * sb, sysv_zone_t nr)
+{
+        struct sysv_sb_info * sbi = SYSV_SB(sb);
+        struct buffer_head * bh;
+        sysv_zone_t *blocks = sbi->s_bcache;
+        unsigned count;
+        unsigned block = fs32_to_cpu(sbi, nr);
+
+        /*
+         * This code does not work at all for AFS (it has a bitmap
+         * free list).  As AFS is supposed to be read-only no one
+         * should call this for an AFS filesystem anyway...
+         */
+        if (sbi->s_type == FSTYPE_AFS)
+                return;
+
+        if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
+                printk("sysv_free_block: trying to free block not in datazone\n");
+                return;
+        }
+
+        lock_super(sb);
+        count = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+
+        if (count > sbi->s_flc_size) {
+                printk("sysv_free_block: flc_count > flc_size\n");
+                unlock_super(sb);
+                return;
+        }
+        /* If the free list head in super-block is full, it is copied
+         * into this block being freed, ditto if it's completely empty
+         * (applies only on Coherent).
+         */
+        if (count == sbi->s_flc_size || count == 0) {
+                block += sbi->s_block_base;
+                bh = sb_getblk(sb, block);
+                if (!bh) {
+                        printk("sysv_free_block: getblk() failed\n");
+                        unlock_super(sb);
+                        return;
+                }
+                memset(bh->b_data, 0, sb->s_blocksize);
+                *(__fs16*)bh->b_data = cpu_to_fs16(sbi, count);
+                memcpy(get_chunk(sb,bh), blocks, count * sizeof(sysv_zone_t));
+                mark_buffer_dirty(bh);
+                set_buffer_uptodate(bh);
+                brelse(bh);
+                count = 0;
+        }
+        sbi->s_bcache[count++] = nr;
+
+        *sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+        fs32_add(sbi, sbi->s_free_blocks, 1);
+        dirty_sb(sb);
+        unlock_super(sb);
+}
+
+sysv_zone_t sysv_new_block(struct super_block * sb)
+{
+        struct sysv_sb_info *sbi = SYSV_SB(sb);
+        unsigned int block;
+        sysv_zone_t nr;
+        struct buffer_head * bh;
+        unsigned count;
+
+        lock_super(sb);
+        count = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+
+        if (count == 0) /* Applies only to Coherent FS */
+                goto Enospc;
+        nr = sbi->s_bcache[--count];
+        if (nr == 0)  /* Applies only to Xenix FS, SystemV FS */
+                goto Enospc;
+
+        block = fs32_to_cpu(sbi, nr);
+
+        *sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+
+        if (block < sbi->s_firstdatazone || block >= sbi->s_nzones) {
+                printk("sysv_new_block: new block %d is not in data zone\n",
+                        block);
+                goto Enospc;
+        }
+
+        if (count == 0) { /* the last block continues the free list */
+                unsigned count;
+
+                block += sbi->s_block_base;
+                if (!(bh = sb_bread(sb, block))) {
+                        printk("sysv_new_block: cannot read free-list block\n");
+                        /* retry this same block next time */
+                        *sbi->s_bcache_count = cpu_to_fs16(sbi, 1);
+                        goto Enospc;
+                }
+                count = fs16_to_cpu(sbi, *(__fs16*)bh->b_data);
+                if (count > sbi->s_flc_size) {
+                        printk("sysv_new_block: free-list block with >flc_size entries\n");
+                        brelse(bh);
+                        goto Enospc;
+                }
+                *sbi->s_bcache_count = cpu_to_fs16(sbi, count);
+                memcpy(sbi->s_bcache, get_chunk(sb, bh),
+                                count * sizeof(sysv_zone_t));
+                brelse(bh);
+        }
+        /* Now the free list head in the superblock is valid again. */
+        fs32_add(sbi, sbi->s_free_blocks, -1);
+        dirty_sb(sb);
+        unlock_super(sb);
+        return nr;
+
+Enospc:
+        unlock_super(sb);
+        return 0;
+}
+
+unsigned long sysv_count_free_blocks(struct super_block * sb)
+{
+        struct sysv_sb_info * sbi = SYSV_SB(sb);
+        int sb_count;
+        int count;
+        struct buffer_head * bh = NULL;
+        sysv_zone_t *blocks;
+        unsigned block;
+        int n;
+
+        /*
+         * This code does not work at all for AFS (it has a bitmap
+         * free list).  As AFS is supposed to be read-only we just
+         * lie and say it has no free block at all.
+         */
+        if (sbi->s_type == FSTYPE_AFS)
+                return 0;
+
+        lock_super(sb);
+        sb_count = fs32_to_cpu(sbi, *sbi->s_free_blocks);
+
+        if (0)
+                goto trust_sb;
+
+        /* this causes a lot of disk traffic ... */
+        count = 0;
+        n = fs16_to_cpu(sbi, *sbi->s_bcache_count);
+        blocks = sbi->s_bcache;
+        while (1) {
+                sysv_zone_t zone;
+                if (n > sbi->s_flc_size)
+                        goto E2big;
+                zone = 0;
+                while (n && (zone = blocks[--n]) != 0)
+                        count++;
+                if (zone == 0)
+                        break;
+
+                block = fs32_to_cpu(sbi, zone);
+                if (bh)
+                        brelse(bh);
+
+                if (block < sbi->s_firstdatazone || block >= sbi->s_nzones)
+                        goto Einval;
+                block += sbi->s_block_base;
+                bh = sb_bread(sb, block);
+                if (!bh)
+                        goto Eio;
+                n = fs16_to_cpu(sbi, *(__fs16*)bh->b_data);
+                blocks = get_chunk(sb, bh);
+        }
+        if (bh)
+                brelse(bh);
+        if (count != sb_count)
+                goto Ecount;
+done:
+        unlock_super(sb);
+        return count;
+
+Einval:
+        printk("sysv_count_free_blocks: new block %d is not in data zone\n",
+                block);
+        goto trust_sb;
+Eio:
+        printk("sysv_count_free_blocks: cannot read free-list block\n");
+        goto trust_sb;
+E2big:
+        printk("sysv_count_free_blocks: >flc_size entries in free-list block\n");
+        if (bh)
+                brelse(bh);
+trust_sb:
+        count = sb_count;
+        goto done;
+Ecount:
+        printk("sysv_count_free_blocks: free block count was %d, "
+                "correcting to %d\n", sb_count, count);
+        if (!(sb->s_flags & MS_RDONLY)) {
+                *sbi->s_free_blocks = cpu_to_fs32(sbi, count);
+                dirty_sb(sb);
+        }
+        goto done;
+}